ES2939745T3 - fan and electric motor - Google Patents

Abstract

The impeller (8) has impeller vanes (23) connected with a base body (19) on a lower side. The vanes form impeller tips (29) which are directed away from the bottom in relation to an extension of the impeller in the direction of a rotation axis (y). The tips overlap the body, and/or the blades end with a distance to an overlap of the edge of the body on the lower side forming a diffuser region (30). A maximum extension radius of the blades lies in a range between 1.5 and 0.6 times the maximum extension radius of the base body in a view from above. An independent claim for an electric motor is also included. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

fan and electric motor

The invention relates to a fan wheel according to the characteristics of claim 1.

Fan wheels of the type in question are known. These find use in particular in connection with an electric motor. Such a fan wheel is designed for rotary drive thereof around the axis of rotation by means of the electric motor, a draft of air being generated by the fan wheel when the electric motor is in operation. In known configurations, this air stream serves at least partly to cool the electric motor.

Known fan wheels for this purpose have, first of all, a rotosymmetric base body in which fan wheel blades are arranged on the outside of the wall. These fan wheel blades have, with reference to the axis of rotation, an inner radial blade inlet edge and an outer radial blade outlet edge, said edges are connected to the fan wheel, with reference to a plan view, by means of a longitudinal edge of the palette. In particular, the blade entry edges of the fan wheel blades form the fan wheel tips remote from the connection area of the fan wheel blades on the base body.

In the fan wheel known from DE 1097 077 B, the fan wheel tips lie in a common oriented plane which runs in the direction of the axis of rotation with respect to an upper base body plane adjoining below or right on this one. From EP 2410 183 A2 a fan wheel is known in which the fan wheel tips do indeed protrude somewhat above the upper base body plane, however with an irrelevant surface area.

Furthermore, the fan wheel blades project from a lower base body plane in a radial direction.

Proceeding from the stated state of the art, the invention is concerned with the task of specifying a fan wheel, which is advantageous with favorable configuration from the production-technical point of view, in particular also with respect to performance.

This mission is achieved with the object of claim 1, reference being made to the fact that the fan wheel tips protrude from the base body, that all the fan wheel tips are arranged in a common plane, oriented transversely with respect to the axis of rotation , which is spaced upwards in the direction of the axis of rotation from an upper base body plane, that this distance is chosen such that, with reference to a side view towards a fan wheel blade above the body plane upper base, a partial blade area is set which corresponds to 20 to 50% of the entire blade surface and that in a projection in the direction towards a lower base body plane, the fan wheel blades do not protrude from an edge of circumferential bottom edge.

The fan wheel configured in this way has proven to be advantageous with respect to performance and also to producibility. The fan wheel tips of the inner radial blade entry edges protrude from the base body in the direction of the axis of rotation, and may also correspond to a distance dimension between an upper base body plane and the wheel tips fan at approximately a multiple of 0.2 to 0.8 of the height, considered in the direction of the axis of rotation, of the base body between a lower and upper base leather plane.

On the bottom side, the fan wheel blades terminate with a distance from a lower edge edge or a lower base body plane, this also with reference to the connection of an outer radial blade entry edge at the bottom. base body. The distance dimension, considered in the direction of the axis of rotation, of the end of each of the fan wheel blades with respect to the plane of the lower base body corresponds, in a preferred configuration, to the multiple of 0.2 to 1 of the dimension of anterior projection of the fan wheel tips above the base body, more preferably to the multiple of 0.1 to 0.5 of the distance dimension, considered in the direction of the axis of rotation, between the plane of the upper base body and lower. This lower area, correspondingly without a vane connection, forms a diffuser region, in particular a diffuser subsection, which, due to the described constant rising outer contour of the base body, starting from the plane considered to be transverse to the axis of rotation, in which the fan wheel blades terminate in the base body, widens constantly, with reference to the axis of rotation, radially outwards to the lower base body plane. In a plan view or in a projection in the direction of the axis of rotation onto the plane of the lower base body, the fan wheel blades do not project from the circumferential bottom edge edge of the base body. The fan wheel blades may, in plan view, be formed without mutual overlap. This offers advantages, in particular from the technical production point of view. In particular, in a fan wheel with a single-piece base body made of homogeneous material and fan wheel blades molded into it, more particularly produced in a plastic spray gun method, this results in advantages over demoulding after the spraying process. A demolding of this type is, according to the proposed solution, possible without sliding guide. Rather, the molded elements which are located in particular between the fan wheel blades in the course of the spraying process are, in a preferred embodiment, helically shaped on the lathe in the direction towards the fan wheel tips. These molded elements can be correspondingly arranged in a common upper tool, through which the rotational movement is achieved during demoulding. The fan wheel blades are arranged dispersed, in a plan view or in a projection in the direction of the axis of rotation, on the lower base body plane, with the largest diameter, preferably without such a projection a subsection of one fan wheel blade covers a partial area of another fan wheel blade.

In a preferred configuration, four to eight fan wheel blades are provided. More preferably, the fan wheel has six fan wheel blades, the fan wheel blades being in any case arranged evenly distributed in the circumferential direction of the fan wheel with respect to the axis of rotation. Also, the fan wheel blades are, in a more preferred configuration, all configured the same, as well as all arranged the same on the outer surface of the base body.

A blade entry edge that runs straight, with respect to the internal radial axis of rotation, encloses an angle, in a more preferred configuration, of 35 to 55 degrees with respect to the axis of rotation. Thus, a particularly radially oriented blade inlet edge, however with reference to a side view towards the fan wheel blade, starting from a blade toe line, is preferably radially outwardly inclined by approximately 45 degrees.

In a side view towards the fan wheel, the diffuser region on the base body's foot side and not connected with vanes has an extension dimension, in particular along the outer contour, which preferably corresponds to a multiple of 0.5 to 0.9 of the extension dimension of the longitudinal edge of the blade in plan view.

The diffuser region of the fan wheel has, in a preferred configuration, a meridian length which corresponds to a multiple of 0.3 to 0.4 of the meridian length of the longitudinal edge of the blade.

In a more preferred configuration, a radius dimension of the transition from the blade outlet edge to the base body corresponds to a multiple of 0.7 to 0.95, more preferably a multiple of 0.8 to 0.9 of the maximum dimension of radius of the vane exit edge. This results, in a preferred configuration, in a blade outlet edge, which, starting from the connection to the base body, ascends radially outwards, this more preferably enclosing an angle with respect to the axis of rotation of 15 to 35 degrees, more preferably of about 25 degrees.

The length of the longitudinal edge of the blade is given, with respect to a toe line of the fan wheel blade in the region of connection to the base body, preferably in a ratio of 0.5 to 0.9. Thus, more preferably, the meridian length of the longitudinal edge of the blade is less than the meridian blade length in the region of the toe line, this most preferably in a ratio of 0.6 to 0.8.

The base body has an essentially conical outer contour. Correspondingly, with reference to a vertical section through the fan wheel, the outer contour, starting from a radially outward to radially inward lower base body plane, is configured to be constantly and preferably uniformly ascending, and may be given in the contour travel from radially out to radially in, also a transverse deviation from the contour extent of up to 20 percent, more preferably up to 10 percent of the contour length between the lower and upper base body plane on both sides with about a conical contour line. Also, within the conical outer contour, the angle of inclination of the outer contour with respect to the axis of rotation can be different along the length of the outer contour, thus, more preferably, it presents a deviation of 1 to 5 degrees with respect to the preferred 30 to 60 degrees, more preferred 45 degrees, inclination of the outer contour with respect to the axis of rotation.

Furthermore, it is preferred that the blade trailing edge is rounded in cross section, in particular in a section that runs parallel to the longitudinal edge of the blade. This radially outer, rounded vane trailing edge and therefore preferably associated with the receding side, preferably has a radius corresponding to a multiple of 0.4 to 0.9, more preferably a multiple of 0.5 to 0 .8 of the thickness of the palette. The thickness of the blade is here in particular measured transverse to the direction of extension of the longitudinal edge of the blade, this is more preferably measured at a distance from the trailing edge of the blade, which corresponds to the radius dimension of the trailing edge palette plus 10 to 30 percent. Preferably, the radius is provided on the receding side of the blade.

In a more preferred embodiment, provision is made for the blade inlet edge on the fan wheel in plan view to have a flat surface that extends substantially transversely to the longitudinal direction of the blade.

Further advantageous, in particular with respect to performance, is that a fan wheel blade in plan view extends over a preferred circumferential angular range (blade wrap angle), measured from the axis of rotation, from 35 to 60 degrees. Preferred in this connection is a blade enveloping angle of 40 degrees to 55 degrees, in particular starting from the preferably strictly radially oriented blade leading edge in plan view, to the base region of the blade trailing edge. palette in the transition to the base body.

An electric motor with a rotor and a stator can be provided, as well as a motor-driven fan wheel for cooling the electric motor, the rotor axis corresponding to an axis of rotation of the fan wheel, furthermore being connected in the direction of air flow to the fan wheel a fixed guide vane arrangement with respect to the rotor and encircling the stator, furthermore the electric motor being accepted in a motor housing. An electric motor of this type is not the object of the invention.

Electric motors of this type are used in particular to drive shafts or the like in devices, more preferably in hand devices. Also, by means of electric motors of this type, a current of air can be passed through using the fan wheel, so that a motor/fan unit thus formed can find application, for example, for use in a handheld vacuum cleaner or similar. Preferably, at least a part of the air stream is used to cool the electric motor, in particular to cool the rotor and stator. The guide vane arrangement, which is connected to the fan wheel in the flow direction, preferably serves in the form of a diffuser for homogenizing the air stream, in particular for homogenizing the air blown essentially radially outwards into the region of the fan wheel in the direction of an air flow directed at least substantially in the direction of the axis of rotation of the fan wheel or of the rotor.

It can be provided that the guide vanes are configured in a radial interspace of a double-walled current guide part enclosing the electric motor, with a homogeneous material configuration, more preferably, at the same time also a one-piece configuration with the walls of the current guide part. Correspondingly, the guide vanes are preferably connected both radially in and radially out to the flow guide part, this more preferably in the event of a possible production of the flow guide part in the plastic spraying process by spray gun with configuration of a single piece, with homogeneous material. In addition to an advantageous flow guide, this also results in cost-effective production of the flow guide part together with the guide vanes. The inner wall of the stator-encircling current guide part, more preferably oriented coaxial with respect to the axis of rotation of the rotor, and the outer wall of the current guide part, moreover preferably arranged concentric with respect to the inner wall, are connected each other through the guide vanes arranged in the annular space thus created between the walls. The current guide part in this case more preferably forms a central component for the electric motor, to which all other components are attached, such as in particular the stator with the rotor and the rotor shaft, in addition to this, preferably also a fan wheel cover.

Provision can be made for the fan wheel to have a base body with a given outer contour in longitudinal cross section, ie a plane that accepts the axis of rotation in its extension, and for an outer contour of the inner wall of the guide part to current connects to the outer contour of the base body.

The outer contour of the inner radial wall of the flow guide part correspondingly accepts, in particular in the region of transition towards the fan wheel, the outer contour, in particular of the end region of the fan wheel facing towards the Correspondingly, more preferably, the current guide part forms an extension of the outer contour of the fan wheel with respect to the contour.

More preferably, the outer contour of the inner wall of the flow guide part runs in a constant curve, with a local radius of curvature increasing in the flow direction, that is, in particular starting in the region of the contour transition towards the fan wheel . Preferably, the local radius of curvature extends from the preferably conical fan wheel body in a meridian section to a region parallel to the axis, in which region the guide vanes also preferably end, considered in the flow direction.

A guide vane, preferably all of the guide vanes, run curved in a transverse longitudinal section with respect to its extension in the flow direction, this with a configuration, viewed in the direction of the axis of rotation of the fan wheel, on one intake side of guide vane and a return side of the guide vane covered by the intake side of the guide vane. The radius of curvature of each of the guide vanes is, more preferably, chosen to be invariant along the entire length of extension, more preferably, at least approximately invariant with a deviation of up to 10 or 20 percent with respect to a radius average down and/or up. Correspondingly, the guide vanes are curved with respect to the circumference of the inner and/or outer wall of the flow guide part in such a way that the retreating side of the guide vane runs convexly curved, viewed away from the guide vane, and the intake side of the concave guide vane, considered away from the guide vane.

The inlet side of the guide vane, which is in danger of becoming loose during operation of the electric motor, preferably has a cross-sectional narrowing in meridian section, and correspondingly preferably a narrowing between the outer surface of the inner wall and the inner surface of the inner wall. wall outside of the flow guide part, this in comparison with the receding side of a guide vane. Correspondingly, current acceleration occurs in the region of the intake side of each of the guide vanes in operation of the electric motor. This has been shown to be positive in avoiding detachments and, because of this, lower yields and noise.

On the vane retreat side, a drop of non-constant cross section is preferably provided with a depth that corresponds to a multiple of 1 to 4 of the turbulent boundary layer thickness. Consequently, considerable current losses do not occur, rather the impact eddy causes good cooling of the stator package. The turbulent boundary layer forms practically across the entire surface of the vane receding side above it. It can have a thickness in the range of 0.2 to 2.2 mm, more preferably in the range of 0.3 to 2 mm.

In a more preferred embodiment, it is provided that the outer face of the inner wall of the current guide part has circumferentially distributed rebound regions in a longitudinal cross section, which lead to a radial widening of the distance between the outer surface of the inner wall and the inner surface of the outer wall of the current guide piece.

In this case, the contour of the outer surface of the inner wall runs in a meridian section in the rebound regions, preferably parallel to the axis of rotation. Alternatively, the inner wall encloses in the rebound regions an acute angle with respect to the axis of rotation, said angle however, in a more preferred configuration, is chosen to be smaller than the contour of the outer surface of the inner wall, considered in the circumferential direction , outside the rebound regions, more particularly, in the intake side region of each of the guide vanes.

The rebound region is associated, with reference to a plan view, preferably to the receding side of the guide vane.

In particular, for direct cooling by air flow, the inner wall of the flow guide part preferably has breaks towards the stator. Correspondingly, the stator is located behind the ruptures, more preferably window-shaped, free for the flow of cold air. Thus, one to eight, more preferably two to four, such breaks are provided, most preferably across the circumference of the inner wall, one break being provided in each case, considered in the circumferential direction, between two guide vanes.

In a more preferred embodiment, the inner wall of the flow guide part is connected in one piece and made of homogeneous material to a bearing region for the fan wheel, the bearing region as well as the inner and outer walls more preferably forming of the current guide part as a whole, preferably the motor housing or a subsection thereof.

In this context, it has further proved to be an advantage when, as more preferably, with reference to a longitudinal cross section of the bearing region of the fan wheel configured in the fixed region of the motor housing, it overlaps the base body. of the fan wheel, in particular in a vertical overlap, considered in the direction of the axis of rotation. Accordingly, it is preferred that the fan wheel covers, in particular with its base body, the bearing region of the motor housing.

The bearing region of the motor housing extends in a more preferred configuration, starting from a lower base body plane of the fan wheel or starting from a parting plane oriented transverse to the axis of rotation, between the contour of the base body of the fan wheel and the outer contour of the inner wall, conical in shape, reducing in diameter from radially outside to radially in and in the direction towards the fan wheel.

The bearing region is formed, in a more preferred configuration, by two bearings, in particular rollers, more preferably rollers, spaced apart in the direction of the axis of rotation. The gravitational point of the fan wheel and bearing region assembly is preferably between the mentioned bearings, in the axial direction. More preferably, offset towards the upper bearing, on the fan wheel side.

More preferably, the bearings can be biased in the axial direction by a compression spring such that they are generally pressed away from one another.

In addition, the point of gravity is preferably transverse to the axis of rotation in the region of the conical shape of the bearing region of the motor housing.

The lower bearing is, preferably in a transverse direction with respect to the axis of rotation, in overlap with respect to a winding of the electric motor.

The absolute dimensions of the fan wheel are approximately 25 to 35 mm, more preferably approximately 30 mm, with respect to the largest (lower) diameter, the largest height 15 to 25 mm, more preferably approximately 20 mm.

The aforementioned point of gravity is, moreover, preferably in absolute dimension approximately 3 to 8 mm, preferably 5 to 6 mm, below the upper bearing.

The basic body of the fan wheel is preferably configured, in particular with respect to its outer contour in a longitudinal cross section, also at least approximately conical, this more preferably also with respect to an internal contour, so that it is essentially configured a base body in the shape of a circular conical trunk. In this case, its inner contour runs in a meridian section, preferably at least approximately parallel to the outer contour of the base body, more preferably at the same time also at least approximately parallel to the outer contour of the bearing area.

Thus, in the region of overlap, a groove is formed between the outer surface of the bearing region and the inner surface of the base body of the fan wheel which rises from radially outwards to radially inwards. In this case, a groove dimension between the outer surface of the bearing region and the inner surface of the base body, preferably measured perpendicular to the surfaces, is chosen that preferably corresponds to the thickness, considered in the same direction, of the groove. base body wall and/or bearing region wall.

Furthermore, it is preferably provided that more guide vanes are provided than fan wheel blades. Thus, the flow guide part has, in a preferred configuration, twelve to twenty, more preferably sixteen guide vanes, while the fan wheel preferably has four to eight, more preferably six fan wheel blades. In addition, provision is preferably made here that the number of guide vanes corresponds to a multiple of 2 to 5 of the number of fan wheel blades.

In order to avoid direct sound radiation from the fan wheel to the outlet region of the flow guide part, it is more preferably provided that the maximum radius dimension of the fan wheel blades is smaller than the radius dimension in the outer wall region of the inner wall of the current guide piece. In this regard, a ratio of 1:1.1 to 1:1.5 is preferred. The necessary acoustic reflection in a preferably provided fan cover wall additionally reduces noise.

The relatively constant gap in its height between the preferably conical inner face of the blower impeller and the also preferably conical shaped bearing region ensures that liquids and other foreign particles during operation of the electric motor are kept away from a bearing preferably provided in the bearing region. Also in horizontal use and with stationary electric motor, liquid is led downwards through a formed "water groove" and is kept away from the bearing, the base body forming a rupture edge in the region of its circumferential edge edge in the lower base body plane.

The preferred ratio of fan wheel blades to guide vanes of 6:16 reduces tonal noise ratios.

Furthermore, an electric motor with a rotor and a stator is described, as well as a fan wheel driven by the rotor for cooling the electric motor, an axis of the rotor corresponding to an axis of rotation of the fan wheel, the motor being electrical accepted in a motor housing with a bearing region for a rotor shaft of the fan wheel. This electric motor is also not part of the invention.

The subject matter electric motors are known, as described. With respect to the known state of the art, a technical problem lies in specifying an electric motor of the subject in question, which enables an advantageous mounting, in particular of the rotor in the motor housing.

A possible solution of the object is given according to a first concept in an electric motor, in which it is intended that the rotor shaft is housed through one or more bearings included in a bushing and that several bearings are configured in the bearing region. Ridges running in the direction of the rotor shaft, arranged distributed with respect to the circumference of the bushing, which bear at least partly directly on an outer surface of the bushing. The bushing in this case more preferably comprises the bearing(s) in the region of a bearing outer ring, which is more preferably non-rotatingly connected to the outer ring, most preferably as a result of a compression connection. By means of this bushing, the rotor shaft is accommodated in the motor housing or in the bearing region, for which the bearing region has a corresponding bearing for the bushing. The ribs provided in this bearing area preferably run parallel to the rotor axis. Through the ribs, a support is given, at least partly punctual or linear, of the bushing within the bearing region. In a more preferred configuration, only a part of the ribs provided bear on the outer surface of the bushing, while other ribs provided, if necessary, with reference to the rotor axis, they end with a radial distance with respect to the bushing. As a result, an advantageous positioning of the rotor shaft or the rotor shaft sleeve in the motor housing can be achieved overall. Assembly is simplified overall.

It can be provided that one or more ribs are formed which have a play-fit with respect to the outer surface of the sleeve. Correspondingly, these ribs terminate radially inwardly in the direction of the rotor axis at a distance from the outer surface of the rotor shaft sleeve. The distance is preferably 0.1 to 1 mm, more preferably 0.2 to 0.5 mm. This clearance fit preferably serves to support the orientation of the rotor shaft sleeve within the bearing region. Preferably, a plurality of ribs are additionally provided to form the play fit, which ribs are arranged more preferably evenly distributed over the circumference. Thus, more preferably, two to six, in particular three to four, such ribs are provided to form a play fit.

In addition, it is preferably provided that one or more ribs are formed that have a positive fit with respect to the outer surface of the sleeve. Also here, preferably several ribs are arranged evenly across the circumferential of the socket to be attached, thus in particular two to six, more preferably three to four such ribs. The radially inwardly pointing free front surfaces are arranged along a circular line with reference to a horizontal projection or else a cross section considered transverse with respect to the rotor axis, said circular line preferably running concentric with respect to the axis of rotation. rotor. The diameter of this circular line corresponds, in a preferred configuration, to the outer diameter of the bushing in the region of the outer wall. In particular, the ribs abutting on the outer surface of the bushing lead, in a preferred embodiment, to a force fit of the bushing of the rotor shafts. This forced fit is, in one possible configuration, the only fixation of the rotor shaft in the motor housing. In a preferred embodiment, the press fit serves primarily for pre-positioning of the rotor shaft in the motor housing until the rotor shaft or the bushing is finally fixed by other measures.

A final fixing of the rotor, in particular of the sleeve of the rotor shaft in the bearing region, is achieved, in a more preferred embodiment, by adhesion. In this context, several ribs have proven to be advantageous for forming a press-fit, since they securely hold the bushing and therefore the rotor shaft in the found position, at least as long as the adhesive wears off. has hardened The adhesive can in this case be applied both in the region of the ribs to form a press fit, and also in the region of the ribs to form a play fit. Preferred is a gap-filling application of adhesive in the region of the radially inwardly pointing free front faces of the ribs to configure the play-fit.

Also, it is preferably provided that a part of the ribs, with respect to a front face constituting the play-fit or press-fit, extends over a greater length of the front face than another part of the ribs. In a preferred alternating arrangement of ribs for forming a clearance fit and ribs for forming a press fit, in particular one group of ribs in the direction of the rotor axis is configured longer than the other group of ribs.

Thus, it is preferably provided that the play-fit ribs extend over a greater length than the press-fit ribs. The clearance-adjusting ribs serve, above all, for the approximate orientation and stabilization of the bushing or the rotor shaft in the desired orientation. In this case, the clearance-fitting ribs extend, in a more preferred configuration, at least approximately, more preferably completely over the axial length of the sleeve, in addition, if necessary, also extend on one or both sides beyond the cap. On the other hand, the snap-fit ribs that serve at least provisionally to fix the bushing are shorter, in this case preferably they have an axial length corresponding to the multiple of 0.3 to 0.9, more preferably to the multiple from 0.4 to 0.7 of the length, considered in the axial direction, of the ribs for adjustment with play.

In a more preferred configuration, two axially spaced rotor shaft bearings are provided. Its bearing outer rings are preferably comprised by the bushing, more preferably rotationally resistant to the bushing. In a preferred configuration, the press-fit ribs extend essentially in the region of the sleeve between the bearings, thus correspondingly more preferably in the region of the axial spacing between the two bearings. This prevents interference of the bearings by pressure forces occurring in the radial direction. The pressure forces act correspondingly preferably outside the region of direct interference.

The end face of a clearance-fit rib has, in a preferred configuration, a circumferential extension of 0.5 to 5 mm. Correspondingly, a flat front face is provided for each of the ribs for adjustment with play, this front face being, in a more preferred configuration, configured, with reference to a transversal section considered transverse with respect to the rotor axis, rectilinear or , as is most preferred, in the form of a circular section, concentric with respect to the rotor axis. The front face of a press-fit rib, preferably Of all the ribs that are press fit, it is preferably rounded, with a bulge pointing in the direction of the rotor axis. Thus, in the mounting position of the bushing, a linear bearing of the casing surface of the bushing on each of the press-fit ribs is preferably achieved.

The ranges or ranges of values or multiple data sets listed above and below also include, with regard to the disclosure, all intermediate values, in particular in steps of 1/10 of the respective dimension, if any, therefore also dimensionless, in particular the multiple of 1.01 etc., on the one hand, to limit the range limits mentioned from below and/or above, alternatively or additionally however also with regard to the disclosure of one or more single values of the range indicated in each case.

In the following, the fan wheel according to the invention and details of the non-inventive electric motor are explained by means of the attached drawing, which however only represents exemplary embodiments. A part, which is explained only with reference to one of the exemplary embodiments and which in another exemplary embodiment is not (precisely) replaced by another part because of the particularity demonstrated therein, is thereby also described for this other exemplary embodiment. example of embodiment as part in any case possibly present. In the drawing, it shows:

Fig. 1 an electric motor with a fan wheel of the type in question in the subject, in a partly broken perspective representation;

FIG. 2 the electric motor with fan wheel in a vertical sectional representation;

FIG. 3 the motor housing with a current guide part in a single perspective illustration, partly in section;

Fig. 4 the fan wheel in a single perspective representation;

Fig. 5 the plan view on the fan wheel according to the arrow V in figure 4;

Fig. 6, the side view according to arrow VI in Figure 5;

Fig. 7, the side view according to arrow VII in Figure 6;

Fig. 8, the VIM-VIM section in Figure 5;

Fig. 9, in a single representation, a fan wheel blade in side view;

Fig. 10, the plan view on the pallet;

FIG. 11 the motor housing in a first embodiment in individual perspective representation; Fig. 12 the plan view for this according to arrow XII in Fig. 11;

Fig. 13, the section according to the line XMI-XMI in Figure 11;

Fig. 14, the section according to line XIV-XIV in Figure 11;

Fig. 15, the section according to XV-XV in Figure 14;

FIG. 16 shows the motor housing in a detailed sectioned perspective view, which relates to a second embodiment.

An electric motor 1 with a stator 2 and a rotor 3 arranged coaxial with respect to the stator 2, inside the stator 2, is shown and described first with reference to Figure 1.

The rotor 3 has a rotor axis x which simultaneously passes centrally through the stator 2. The axis is additionally supported centrally by a rotor shaft 4 connected to the rotor 3 in a rotation-resistant manner.

Furthermore, the stator 2 is supported in a motor casing 5 with the rotor 3 rotatable around the rotor x-axis inside, said motor casing 5 essentially completely enclosing the stator 2 with reference to the rotor x-axis.

Part of the motor housing 5 is a current guide part 6, which extends essentially into a wall 7 of the motor housing, preferably completely circumferential. More preferably, the current guide part 6 is made in one piece with the wall 7 of the motor housing and, more preferably, made of homogeneous material. In a preferred configuration, the motor housing 5 formed in this way is a hard plastic part produced in a spray gun process.

The electric motor 1 serves to drive a fan wheel 8. To do this, one end of the rotor shaft 4 projects freely outside the electric motor 1, in particular beyond the stator and, more preferably, beyond the current guide part 6. This rotor shaft end 9 is more preferably configured in an axially opposite region with respect to the stator 2.

The rotor shaft 4 is accommodated, in particular in front of the free outlet of the rotor shaft end 9 above the bearing 10 arranged in the motor housing 5, more preferably in the current guide part 6, which, in the The illustrated exemplary embodiment essentially consists of two ball bearing sections spaced from one another in the axial direction and here mutually supported by means of a compression spring.

Rotor shaft end 9 is configured for rotation-resistant fixing of fan wheel 8.

The fan wheel 8 as well as the bearing region 11 of the flow guide part 6 preferably extend through an opening edge edge 12 of the motor housing oriented transverse to the rotor axis x, plus preferably circumferential.

Furthermore, in particular the fan wheel 8 as well as the bearing region 11 of the flow guide part 6 are covered by a fan cover 13, which in particular encloses the fan wheel 8 in the form of a spherical cap, this enabling free rotation of the fan wheel 8 around its axis and rotation. The y axis of rotation more preferably corresponds to the x axis of the rotor.

The fan cover 13 has a circumferential fan cover wall 14, which, in the placement position of the fan cover 13 in the motor housing 5, at least starting from the edge edge 12 of the motor housing, with reference to the extension of the x-axis of rotor, it extends to a plane above the uppermost plane of extension of the fan wheel.

In addition, the fan cover 13 has a cover 16 through which an air inlet opening 15 passes centrally, preferably oriented transversely to the rotor axis x or to the y axis of rotation of the fan wheel 8 . This can be configured in particular on the outside, ie in particular away from the fan wheel 8, for the connection of an air flow channel.

The air outlet opening 17 is configured, viewed in the axial direction, opposite the air inlet opening 15. This is in particular enclosed by the end of the motor housing wall 7 axially opposite the edge edge 12 of the motor housing.

The fan cover 13 can preferably be attached to the motor casing 5, thus in particular it can also be attached draft-tight, so that air entering the operation of the fan wheel 8 through the opening The air inlet 15 passes through the motor housing 5 essentially in the axial direction, ie parallel to the rotor axis.

For fixing the fan cover 13 to the motor casing 5, projections 18 for fixing screws are formed on both parts associated with a plane of separation between the parts, preferably on the outside of the wall 14 of the fan cover as well as of the wall 7 of the motor casing, oriented radially with respect to the x-axis of the rotor.

The fan wheel 8 shown in individual representations in FIGS. 4 to 8 initially has a base body 19. This is primarily rotosymmetrically formed with a circumferential base body wall 20 which forms essentially a hollow cone. Starting from an axial lower base body plane E ^u , the outer contour of the base body 19 increases from radially outside to radially in to an upper base body plane E ^o . In the region of the plane E ^or of the upper base body, a flat outer contour is achieved, oriented transverse to the y-axis of rotation.

The base body 19 is centrally traversed with a fixing hole 21, which accepts the y-axis of rotation, which continues the flat tapered region through the base body 19, on the inside of the base body wall 20 in a region of Rotosymmetric fixing, in the form of a block as a whole.

The end face of the fixing region 22 oriented in this case on the inner side of the base body wall 20, preferably transverse to the axis y of rotation, which points in the direction towards the lower base body plane Eu, has a distance considered in axial direction with respect to the plane Eu of the lower base body, which corresponds approximately to the multiple of 0.4 to 0.6, more preferably to the multiple of 0.5 of the distance considered in the axial direction of the two planes E ^u and E ^or base body with respect to each other.

Furthermore, on the fan wheel 8 fan wheel blades 23 are arranged. Preferably, six such fan wheel blades 23 are provided, which are arranged evenly distributed along the y-axis of rotation, with reference to a plan view on the fan wheel 8 according to Fig. 5, and are connected to the base body 19 on the ground side. Preferably, in this regard, a one-piece, material-homogeneous configuration of base body 19 and fan wheel blades 23 is preferred. More preferably, the fan wheel 8 thus shaped is produced in a plastic spray gun process.

The configuration of each of the fan wheel blades 23 described in more detail below results in a preferred configuration, as can be recognized in particular from the plan view in Figure 5 , an arrangement of the fan wheel blades 23 fan wheel, in which they are configured without mutual overlap with reference to a plan view. Correspondingly, in a vertical projection in the direction towards the plane E ^u of the lower base body, no subsection of one fan wheel blade 23 covers a subsection of another fan wheel blade 23.

FIGS. 9 and 10 show a fan wheel blade 23 in side view and in plan view, in particular a sectional cutout of the outer contour of the base body 19 being shown in dashed line in the side view.

Each of the fan wheel blades 23 has a blade inlet edge 24 that is radial on the inside with respect to the axis y of rotation, which extends from a connection region of the fan wheel blade 23 to the base body 19 away from of the body 19 base.

Radially outwards, each of the fan wheel blades 23 forms a blade trailing edge 25, which likewise extends from the joining region away from the base body 19.

The blade inlet edge 24 and the blade outlet edge 25 are connected in the region of their ends remote from the base body 19 via a longitudinal blade edge 26 . The line opposite the longitudinal edge 26 of the blade, which joins the ends of the input edge 24 of the blade and the output edge 25 of the blade, correspondingly configured in the region of the connection of the blade 23 of the fan wheel to the body 19 base, is referenced as line 27 footing.

Both the inlet edge 24 of the blade, as well as more preferably the outlet edge 25 of the blade, run elongated in a straight line between the bottom line 27 and the longitudinal edge 26 of the blade.

The blade inlet edge 24 encloses an angle a of preferably 45 degrees with respect to the y-axis of rotation or with respect to a paraxial, this with a corresponding inclination of the blade outlet edge 24 starting from the toe line 27 radially out.

The blade outlet edge 25 is more preferably oriented so that it encloses an angle p of preferably approximately 25 degrees relative to the axis y of rotation in a side view according to the representation in FIG. With respect to a paraxial, this with an inclination of the vane trailing edge 25 starting from the bottom line 27 in the direction of the longitudinal vane edge 26 radially outward.

The longitudinal edge 26 of the blade runs, with reference to a side view according to Figure 9, preferably approximately parallel to the foot line 27 given by the outer contour of the base body 19, moreover, given the In this case, a joining line that runs parallel to the foot line 27 between the blade entry edge 24 and the blade outlet edge 25, remaining partially above or below. Thus, in this connection, a concave configuration of the longitudinal edge 26 of the blade is more preferably provided, viewed from the base body 19 , corresponding to a corresponding dimension of maximum rearward displacement of the longitudinal edge 26 of the blade, with reference to the previously referenced joint line, at most to the multiple of 1 to 2 of the material density, considered transversal with respect to the observation plane in Figure 9, of the fan wheel blade 23. A corresponding convex configuration can also be provided.

The length a of the longitudinal edge 26 of the blade corresponds, in a preferred configuration, to a multiple of 0.6 to 0.8 of the length b of the foot line 27 .

In addition, the configuration of each of the fan wheel blades 23 is chosen such that a dimension c of the radius of the transition from the blade outlet edge 25 to the base body 19 or to the foot line 27, corresponds to the multiple of 0.8 to 0.9 of the dimension d of the maximum radius of the blade exit edge 25 with respect to the axis y of rotation.

The blade surfaces laid by the blade entry edge 24, the blade outlet edge 25, as well as the longitudinal blade edge 26 and the foot line 27, form a return side D and an intake side S. . Oriented towards the receding side D, the blade outlet edge 25 is rounded in cross section, ie more preferably in a section considered to be parallel to the bottom line 27 . Preferably, a radius r of the rounding is provided here, in particular directed towards the receding side D, which corresponds to a multiple of 0.5 to 0.8 of the blade thickness e between the blade surfaces.

In plan view according to the representation in FIG. 10, the pallet entry edge 24 has a planar surface which extends essentially transverse to the longitudinal direction of the pallet.

Furthermore, each of the fan wheel blades 23 is configured and arranged on the base body 19 such that, with reference to a plan view according to Figure 10, measured from the y-axis of rotation fits a circumferential angular region or a blade connection angle ^y , essentially between the region of connection of the blade input edge 24 in the base body 19 and the connection region of the blade output edge 25 in the base body 19, in such a way that preferably 40 to 55 degrees.

More preferably, all fan wheel blades 23 are configured identical, more preferably, in accordance with the description described above by one fan wheel blade 23.

Furthermore, as can be seen in particular from the plan view in FIG. 5, the fan wheel blades 23 are arranged so that they do not protrude from the circumferential floor edge edge of the base body 19 in the region of the plane E ^u of lower base body. Rather, it is preferably provided that, with reference to a plan view, the longitudinal blade edges 26 in the region of the blade trailing edges 25 end with the circumferential bottom edge edge 28 of the base body 19.

The arrangement of the fan wheel blade 23 is provided according to the invention in such a way that the fan wheel tips 29 formed at the transition from the longitudinal edge 26 of the blade to the blade entry edge 24, which form in the direction of the axis and of rotation, the greatest extension considered of the blade 23 of the fan wheel. In addition, all the fan wheel tips 29 are arranged in a common plane E ^sp oriented transversely with respect to the y axis of rotation, said plane E ^sp of fan wheel tips is spaced upwards in the y axis direction from rotation with respect to the plane E ^or of the upper base body. This distance is chosen according to the invention such that, with reference to a side view towards a fan wheel blade 23 according to the representation in FIG. 9, above the plane E ^or upper base body fits a partial blade surface corresponding to 20 to 50 percent of the entire blade surface.

According to the invention, it is also provided that the fan wheel blades 23 terminate at a distance from the edge edge 28 in the region of the blade outlet edges 25 on the base body 19. of soil. The extension dimension f along the outer contour of the base body 19 (compare FIG. 6) of the base area without blades of the base body 19 preferably corresponds to a multiple of 0.6 to 0.8 of the length a of the base body 19 . Longitudinal edge 26 of the blade in plan view.

The base region without blades of the base body 19 forms a diffuser region 30, in particular a diffuser subsection, which is correspondingly rotatable together with the fan wheel 8 about the axis y of rotation.

The current guide part 6 is preferably double-walled, with an outer wall 31, which is preferably formed by the motor housing wall 7, and an inner wall 32 arranged coaxially with respect to it. In the radial gap 33 thus formed, preferably sixteen guide vanes 34 are arranged uniformly around the rotor axis x.

In each case, the guide vanes 34 extend approximately from the edge edge 12 of the engine casing, are blade-shaped in the direction of the air outlet opening 17 and are more preferably connected to both the inner wall 32, as well as the outer wall 31. Preferred in this connection is also a one-piece configuration, with homogeneous material of the guide vanes 34 with the inner and outer walls 31 and 32 .

In the circumferential direction of the flow guide part 6 or of the radial interspace 33, each of the guide vanes 34 has an intake-side vane surface 35 curved to the front and a vane surface 36 behind it. on the receding side correspondingly bulged.

The inner wall 32 of the current guide part 6 extends substantially beyond a plane of the edge edge 12 of the motor housing, forming a bearing region 11.

The outer contour of the inner wall 32, ie the contour facing the radial interspace 33 with reference to a vertical section according to Figure 2, preferably runs in a constant curve, growing, more preferably starting from an end region of the inner wall 32 projecting beyond the edge 12 of the motor housing, the local radius of curvature in the current direction or in the direction towards the end of the inner wall 32 facing the stator. The radius of curvature further increases in such a way that to end in the final region, considered in the current direction, of the inner wall 32, the outer contour becomes a vertical (compare dashed circular lines g and h provided with different increasing radii in the Figure 14).

In particular, the first radius of curvature (compare line g of curvature) considered in the current direction is, in a preferred embodiment, matched to the outer contour of the base body 19, in particular to the outer contour in the diffuser region 30 . For this, the upwardly pointing end of the inner wall 32 is preferably adapted in terms of diameter to the diameter of the base body 19 or of the fan wheel 8 in the region of the edge 28 of the floor edge.

Starting from this end, facing away from the fan wheel 8, of the inner wall 32, a groove-shaped slot 37 is initially inserted radially inward, which runs concentric with respect to the rotor axis x. This essentially encloses the bearing region 11 that is configured rotosymmetric with respect to the rotor axis x, as a whole, preferably in the form of a frustoconical shape. This bearing region 11 sinks, so correspondingly preferred, in the hollow space, comprised by the base body wall 20, of the base body 19, more preferably, in a plane considered transverse to the rotor axis x, which lies directly below the base plane of the fixing region 22 on the fan wheel side.

More preferably, the outer contour of the bearing region 11 rises, with reference to a meridian section, at least approximately parallel with respect to the inner contour of the base body wall 20, in this case, more preferably leaving a gap 38 which rises from radially out to radially in.

In addition, the inner wall 32 presents, viewed in the circumferential direction thereof, rebound regions 39, in these regions the contour of the inner wall 32 pointing in the direction of the radial gap 33 is displaced radially inwards with respect to to the constant curved path. The rebound depth considered with reference to the x-axis of the rotor in comparison with the curved region of the inner wall 32 preferably corresponds to a multiple of 1 to 4 of the thickness of the turbulent boundary layer.

The contour of the outer surface of the inner wall 32 runs in the rebound regions 39 preferably in a straight line, more preferably parallel to the rotor axis x. More preferably, with reference to a plan view or else with reference to a sectional representation according to FIG. 15, all the rebound regions 39 are associated in each case with a receding side 36 of the guide vane of each of the blades 34 directors. Correspondingly, the inlet side 35 of the guide vane in danger of coming loose has a cross-sectional narrowing in comparison with the retraction side 36 of the guide vane, which leads to a current acceleration in the intake side 35 of the guide vane.

In addition, in the region of the inner wall 32 window-shaped openings 40 have been left, through which in particular the stator 2 is exposed. In the operation of the electric motor 1 and correspondingly in the operation of the fan wheel 8, in this way, through the openings 40 a part of the air guided through the current guide part 6 can reach directly to the stator 2 for cooling thereof.

The above-described electric motor 1 with a fan wheel 8 has an improved performance compared to the prior art.

The center of gravity of the fan wheel 8 is shifted in the direction of the bearing 10 in the bearing region 11, whereby an increase in the resonant frequency crucial for bending is achieved.

The diffuser region 30 of the fan wheel 8 is also suitable for balancing the fan wheel 8, preferably removing material on the outer diameter on the inner face of the base body 19. In addition, the diffuser region 30 is suitable for gripping the fan wheel 8 in case of robot manipulation.

Figure 16 shows a second embodiment of the motor casing 5, in particular the bearing region 11.

As shown in FIG. 2, the bearing 10 is made up of two bearing regions spaced apart in the axial direction from one another, which are accepted in a bushing 41 that in particular surrounds the bearing outer ring. This bushing 41 is connected to the outer ring of each of the bearings in a rotation-resistant manner. In another configuration, as schematically represented in Figure 2, the two bearings are biased away from each other in the axial direction by means of a spring, ie kept displaceable at least partially in the axial direction in the bushing 41.

Bushing 41 is more preferably part of rotor shaft 4. Through the bushing 41, the fixing of the rotor shaft 4 in the motor housing 5 takes place, in particular in the bearing area 11 .

In this case, the bearing region 11 initially has a wall 42 which runs concentric with respect to the rotor axis x. It has a free inner diameter which is chosen to be larger than the outer diameter of the bushing 41. Thus, in this connection, an inner diameter of the wall 42 is preferred which corresponds to a multiple of 1.1 to 1.5 of the outer diameter. of bushing 41.

With reference to the inner circumference of the wall 42, several radially inwardly extending ribs are formed starting from the wall 42. In a preferred configuration, these are in each case three play-fit ribs 43 and one force-fit ribs 44. These ribs are arranged uniformly distributed in the whole with reference to the circumference, with play-fitting ribs 43 and force-fit ribs 44 alternating more preferably in the circumferential direction. Thus, more preferably, two adjacent play-fit ribs 43 (however separated from each other by a force-fit rib 44) enclose an angle of preferably 120°. The same is true for the snap-fit ribs 44.

In a more preferred embodiment, the play-fit ribs 43 and the press-fit ribs 44, in particular with respect to their radially inwardly pointing end edges, run parallel to the rotor axis x.

Each of the clearance-fitting ribs 43 has a length l, considered in the direction of extension of the axis, in particular in the region of the front face 45 pointing radially inward, which is preferably matched to the axial length of the bushing 41 Thus, more preferably, the length l of the front face 45 is equal to the length of the bushing 41, being, more preferably in a horizontal projection, the front face 45 preferably arranged in full overlap with respect to the lateral surface of the bushing 41 The front faces 46 of the ribs 44 for force fit have a reduced length l' compared to the length l of the ribs 43 for play. Thus, in a preferred configuration, the length l' of a press-fit rib end face 46 corresponds to approximately 0.4 to 0.6 multiples of the length l of a play-fit rib 43 .

More preferably, the snap-fit ribs 44 are arranged in their axial orientation so that their end faces 46 overlap in a horizontal projection with respect to the side wall section of bushing 41 extending between bearings 10.

The front faces 46 of the press-fit ribs 44 are preferably rounded, more preferably with a bulge (with reference to a cross section) pointing radially inwardly, ie in the direction of the x-axis of the rotor.

In a preferred configuration, a circular line tangent to the front faces 46 of the ribs 44 for force-fitting has a diameter which corresponds to the outer diameter of the bushing 41.

The end faces 45 of the play-fit ribs 43 are comparatively flat in comparison with the front faces 46 of the press-fit ribs 44, in particular with reference to a cross section in the form of a circular segment with a related radius with the x-axis of rotor. Considered in circumferential extension, the width of such an end face is preferably 1.5 to 4 mm.

A circular line connecting the end faces 45 of the play-fitting ribs 43 here has a diameter that is preferably selected to be larger than the outer diameter of the bushing 41 in the region of its lateral surface. Thus, more preferably, a circular line with a diameter corresponding to the multiple of 1.05 to 1.2 of the external diameter of the bushing 41 is chosen. More preferably, with bushing 41 inserted between the lateral surface of the bushing 41 and the face 45 Facing towards this front of the ribs 43 for adjustment with play, a gap results with a dimension, considered in the radial direction, of preferably 0.1 to 0.3 mm.

In order to mount the motor shaft 4 in the motor housing 5, the bushing 41 connected to the motor shaft 4 via bearings 10 is inserted in the bearing area 11 in the axial direction. Both the press-fit ribs 44 as well as the play-fit ribs 43 have insertion chamfers 47, 48 in order to facilitate insertion, which extend downwards in a vertical section from the base of the respective rib to the respective front face.

In particular, the end faces 45 of the play-fitting ribs 43 are pre-provided with an adhesive.

The found position of the sleeve 41 in the bearing region 11, in particular the axial position, is first fixed as a result of a press fit between the press fit ribs 44 and the sleeve supported by this. The press-fit ribs 44 correspondingly hold the sleeve 41 and through this the rotor shaft 4 in their orientation until the adhesive has hardened.

Reference symbol list

1 electric motor

2 stator

3 rotor

4 rotor shaft

5 engine casing

6 piece stream guide

7 motor casing wall

8 fan wheel

9 rotor shaft end

10 bearing

11 bearing region

12 Edge edge of motor casing

13 fan cover

14 fan cap wall

15 air intake opening

16 deck

17 air outlet opening

18 screw fixing boss

19 base body

20 base body wall

21 fixing hole

22 fixation region

23 fan wheel vane

24 pallet entry edge

25 pallet exit edge

26 longitudinal edge of pallet

27 foot line

28 floor edge edge

29 fan wheel tip

30 diffuser region

31 outer wall

32 inner wall

33 radial interspace

34 guide vane

35 intake side of guide vane

36 back side of guide vane

37 slit

38 hollow

39 rebound region

40 break

41 bushing

42 wall

43 adjustment rib with play

44 force fit rib

45 front face

46 front face

47 insert bevel

48 insert bezel

to length

b length

c radius dimension

d radius dimension

e pallet thickness

f extension dimension

_g circle line

h circular line

l length

the length

rradius

x-axis rotor

_and axis of rotation

D reverse side

Eo upper base body plane

E _sp flat nose fan wheel

Eu bottom base body plane

at angle

_P angle

_Y paddle lacing angle

Claims (8)

1. Fan wheel (8) with a rotosymmetric base body (19), with a circumferential base body wall (20) essentially forming a hollow cone, the base body (20) passing centrally through an axis (y) of rotation and constantly ascending, with reference to its outer contour, in a side view from radially outside to radially in, fan wheel blades (23) being provided, which are connected to the base body (19) on the ground side, presenting in addition, each of the fan wheel blades (23), with reference to the axis (y) of rotation, a radially inner blade entry edge (24), which extends away from the base body (19) of a region of union of the fan wheel blade (23) in the base body (19), and each one of the fan wheel blades (23) radially forms a blade outlet edge (25), which in the same way extends away from the base body (19) starting from a connection region in the base body (19), the blade entry edge (24) and the blade outlet edge (25) being furthermore connected in the region its ends remote from the base body (19) through a longitudinal edge (26) of the blade, being at the transition of the longitudinal edge (26) to the input edge (24) of the blade formed tips (29) of a fan wheel, which, considered in the direction of the axis (y) of rotation, form a greater extension of the fan wheel blade (23), the fan wheel blades (23) terminating on the ground side with respect to an edge (28) edge of the base body (19), with formation of a diffuser region (30), with the tips (29) of the fan wheel protruding from the base body (19) and all the tips (29) of the fan wheel fan arranged in a common plane (ESP), oriented transversely with respect to the axis (y) of rotation, which is spaced upwards in the direction of the axis (y) of rotation with respect to a plane (E0) of the upper base body, characterized because this distance is chosen so that with reference to a side view towards a fan wheel blade (23), above the plane (E0) of the upper base body, a partial blade surface corresponding to 20 to 20 is adjusted. 50% of the entire blade surface and that in a projection in the direction towards a lower base body plane, the fan wheel blades (23) do not protrude from a circumferential lower bottom edge edge. Fan wheel according to claim 1, characterized in that a radius (d) of the maximum extension of a fan wheel blade (23) in plan view is between the multiple of 1.0 to 0, 6 of the radius of the maximum extension of the base body. Fan wheel according to one of the preceding claims, characterized in that a blade entry edge (24) running straight with respect to the axis of rotation (y) encloses an angle (a) of 35° to 55°. Fan wheel according to one of the preceding claims, characterized in that an extension dimension (f) of the diffuser region (30), in a side view, corresponds to a multiple of 0.5 to 0.9 of a dimension (a) extension of the longitudinal edge (26) of the blade in plan view, preferably giving the dimension (a) of extension of the longitudinal edge (26) with reference to a line (27) of the foot of the blade (23) of fan wheel, in a ratio of 0.5 to 0.9. Fan wheel according to one of the preceding claims, characterized in that a blade trailing edge (25) extending straight in a side view relative to the axis of rotation (y) encloses an angle (p) of 15 ° to 35°, preferably a radius dimension (c) of the blade outlet edge (25) in the base body (19) corresponding to a multiple of 0.7 to 0.95 of the edge radius dimension (d) (25) pallet outlet. Fan wheel according to claim 5, characterized in that the blade outlet edge (25) is rounded in cross section, a radius (r) of the rounding preferably corresponding to a multiple of 0.4 to 0.9 of the thickness (e) palette. Fan wheel according to one of the preceding claims, characterized in that a fan wheel blade (23) in plan view extends in a circumferential angular range, measured from the axis (y) of rotation, from 35° to 60°. Fan wheel according to one of the preceding claims, characterized in that the fan wheel blades (23) are configured without mutual overlapping in plan view and/or preferably four to eight blades (23) are provided ) of fan wheel.